Abstract:

Water quality has deteriorated in the upper Olifants River system, South Africa, as a result of land use
activities which include mining, agriculture and industries. A health risk assessment was conducted from
2009 to 2011 in the catchment to determine the possible risks local communities face from various
pollutants such as microbials, heavy metals and oestrogen in the river water and vegetation. Aluminium
and manganese accumulated in plants and vanadium and aluminium concentrations found in selective
water samples posed significant health risks when consumed. A quantitative microbial risk assessment
revealed that the combined risk of infection ranged from 1 to 26 percent with the Norovirus posing the
overall greatest health risk. The anticipated disability adjusted life years resulting from drinking
untreated water from these sites are in the order of 10,000 times greater than what is considered
acceptable. The oestradiol activity, caused by endocrine disrupting compounds in the water, measured
above the trigger value of 0.7 ng L−1. Impoverished communities in the area, who partially depend on
river water for potable and domestic use, are exposed to immune-compromising metals that increase
their probability of infection from waterborne diseases caused by the excess microbial pathogens in the
contaminated surface water.